CN106050466A - Piston ring for internal combustion engines - Google Patents

Abstract

The invention relates to a piston ring (1) for an internal combustion engine, provided with a substantially annular base body (2) of a ferrous alloy, said base body (2) being coated with a coating comprising a first bonding layer (10) and at least a first outer layer (11) or a coating (4) of a second outer layer (12), said first outer layer (11) and said second outer layer (12) being deposited on said first bonding layer (10), A plurality of successively deposited first and second outer layers (11, 12) up to a thickness of up to 100 micrometers, so that due to the high adhesion of the coating to the substrate, low internal stress, high hardness and low porosity in the piston ring (1) provides excellent wear resistance.

Description

Piston rings for internal combustion engines

technical field

The invention relates to piston rings for internal combustion engines, in which at least the base body of the piston ring is provided with a multilayer coating composed of nitrides, which is applied by the process of physical vapor deposition and due to the high adhesion of the coating to the base body Excellent wear resistance due to high hardness, low internal stress, high hardness and low porosity.

Background technique

An internal combustion engine basically consists of two main parts: the engine block (provided with one or more cylinders) and the crankshaft assembly or crankshaft assembly to which one or more heads are attached. The crankshaft assembly contains the pistons, connecting rods, and crankshaft, and is responsible for the displacement of the pistons within the cylinders of the engine block. The piston is part of the cylinder, consisting as a rule of a metallic matrix and comprising one or more rings responsible for providing a sliding seal between the outer edge of the piston and the inner wall of the cylinder.

As a rule, more contemporary four-stroke engines utilize three rings on each piston, two compression rings and one oil ring. The two rings located closest to the piston head are named compression rings and serve to prevent leakage of the gas mixture into the interior of the crankcase when the piston performs a compression movement. The third ring of the piston is named the oil ring and has the purpose of scraping excess oil from the cylinder wall, thereby controlling the thickness of the oil film.

Typically, piston rings are formed from a metallic outer substrate coated with at least one coating suitable for contact with the cylinder wall. The function of the coating is very important due to the fact that one seeks to impart to the ring the properties of low sliding friction, high wear resistance, hardness and toughness.

As a rule, the coating is applied by ion-plating processes, in particular physical vapor deposition (PVD), chemical vapor deposition (CVD) or by electroplating processes.

Among the processes used to coat piston rings, the Physical Vapor Deposition (PVD) process presents interesting benefits, such as the possibility of the process operating at very low operating pressures, the possibility of sintering of high-purity materials , increased adhesion of the coating to the substrate due to the possibility of "cleaning" the surface of the substrate by ion impact; uniform coating thickness, control of the crystal structure of the coating, since in most cases no toxic products or solution and the fact that the deposition temperature is relatively low, no sewage or pollutants will be used anyway.

The basic procedures for physical vapor deposition (PVD) are known as evaporation and sputtering. Cathodic arcing (evaporation) produces a rough micro-melting of the target cathode, thereby sputtering droplets of liquid or large particles (liquid particles or solid fragments produced in the cathodic arcing process). These macroparticles can change in size up to about 100 nanometers, the average diameter of these macroparticles is between 5 nanometers and 30 nanometers, and affect many properties of the coating such as friction, wear resistance, corrosion resistance, electrical resistivity, and reflectivity .

Corrosion resistance, for example, is compromised when large particles are incorporated into the coating, likely to be considered interrupted in dense and continuous coatings. As a rule, filters are used considering a possible course of work, however these filters reduce deposition rates and increase complexity and equipment costs.

The PVD sputtering process is an unheated vaporization involving the ejection of atoms or molecules from a source. Evolution of this technology, for example the High Power Pulsed Magnetron Sputtering (HiPIMS) method, offers the possibility to obtain coatings devoid of dense macroparticles, thus enabling their application to piston rings.

At present, prior art piston rings are provided with an outer matrix or sliding matrix provided with a single layer coating of chromium nitride (CrN) to provide wear resistance. The coating is obtained by a cathodic arc PVD process.

When used in engines with high loads and high combustion pressure levels, the coating exhibits fragile properties, resulting in the appearance of microcracks in the matrix of the piston rings due to high internal stresses. These microcracks propagate, causing flakes of the coating to flake off, creating voids in the substrate, and may even scar the surface of the cylinder liner.

Moreover, in addition to the undesired effects for piston ring coatings of creating a rough surface and resulting in a reduced porosity of the sliding substrate, as mentioned above, there is the possibility of forming large particles, with the potential to cause sticking of the coating on the substrate. Possibility of sexual loss.

Prior art documents PI 1102335-0 and PI 1102336-8 of the same ownership as the present invention disclose high power pulsed magnetron sputtering ( HiPIMS) process. Such a deposition procedure imparts high wear resistance in addition to low internal stress.

It should be noted that the coatings presented in the prior art are of the monolayer type, that is to say there is only one deposited layer. Depending on the deposition procedure, the single-layer coating exhibits more or less wear resistance, but does not exhibit sufficient strength and does not appear to be suitable for application on pistons of highly loaded engines.

Therefore, there is a need to provide piston rings in which at least the base body of the piston ring is provided with a multilayer coating composed of nitrides, which due to the high adhesion of the coating to the base body, low internal stress, high hardness and low Excellent wear resistance due to porosity.

Contents of the invention

purpose of invention

The object of the present invention is to provide a piston ring comprising a multilayer coating which ensures excellent wear resistance due to high adhesion of the coating to the substrate, low internal stress, high hardness and low porosity. layer base.

A further object of the present invention is to provide a piston ring comprising a substrate provided with a coating consisting of a metal nitride, which can be deposited by a cathodic arc deposition process or by physical vapor deposition (PVD ) process, coated by the method of high power pulse magnetron sputtering (HiPIMS).

brief description of the invention

The object of the invention is achieved by a piston ring for an internal combustion engine provided with a substantially annular ferrous alloy substrate coated with a coating comprising a first bonding layer and at least a first or a second outer layer, so The first and second outer layers are deposited on the first bonding layer, a plurality of successively deposited first and second outer layers reaching a thickness of at most 100 micrometers, the first outer layer being composed of a doped metal chemical element (x) The doped element is aluminum (Al), the second outer layer is composed of the nitride of the metal chemical element (x), and the first outer layer is provided with a thickness at least greater than twice the thickness of the second outer layer and less than the thickness of the second outer layer. Two times the thickness of the outer layer.

The object of the present invention is also achieved by a piston ring comprising a metallochemical element (x) selected from chromium (Cr) or titanium (Ti) or niobium (Nb), the first and second outer layers being provided with a distance between 1 and 200 nanometers The coating includes a second bonding layer deposited on the first bonding layer, the first bonding layer consists of chromium (Cr) or chromium/aluminum (CrAl), and the second bonding layer consists of doped chromium nitride Composition, the doped element is aluminum (CrAlN) or chromium nitride (CrN), the coating is composed of the first and second bonding layer and the first and second outer layer, showing between 1800 and 2500HV (Vickers hardness) between 3% and 6% porosity and internal stress between 200 and 700MPa (megapascal).

The object of the invention is additionally achieved by a process for obtaining a piston ring for an internal combustion engine, the coating comprising a first bonding layer, a second bonding layer, a first outer layer and a second outer layer, the coating being deposited by a cathodic arc deposition process, Or deposited by physical vapor deposition (PVD) process, by high power pulsed magnetron sputtering (HiPIMS) method.

Furthermore, the object of the invention is achieved by an internal combustion engine comprising at least one piston ring as defined above.

Description of drawings

The invention will be described in more detail based on an example of embodiment embodied in the accompanying drawings, in which:

Fig. 1 shows the top view of the piston ring of the present invention and its components;

Figure 2 shows a depiction of the coating applied to the piston ring of the present invention;

Figure 3 shows a structural depiction of the sequence of deposition of the coating of the invention;

Figure 4 shows a flow diagram of the stages of the process of the present invention;

Figure 5 shows a graphical depiction of a comparative test for wear evaluation between piston rings of the prior art and piston rings of the present invention;

Figure 6 shows a pictorial depiction of a comparative test for the evaluation of the wear performed between a piston ring of the prior art and a piston ring of the invention.

detailed description

The invention relates to a piston ring 1 for an internal combustion engine, which is provided with a substantially annular base body 2 of a ferrous alloy, on which base body 2 is coated a multilayer coating 4 comprising a first A bonding layer 10 and at least a first outer layer 11 or a second outer layer 12 deposited on the first bonding layer 10, a plurality of subsequently deposited first outer layers 11 and second outer layers 12 having a thickness up to 100 microns , thereby providing excellent wear resistance on the piston ring 1 due to the high adhesion of the coating to the substrate, low internal stress, high hardness and low porosity.

For a proper understanding of the invention, an initial description needs to be provided with reference to the use of a piston ring 1 for an internal combustion engine and to the procedure used for applying a coating 4 to a piston ring 1 .

In the usual way, the piston ring 1 is a self-expanding element, that is to say a high expansion force, having as its purpose the gas sealing of the combustion chamber of the internal combustion engine, the communication of the lubricating oil film control on the walls of the cylinder, and its function as The elastic element of the heat transfer element of the piston box cylinder.

The piston ring 1 is subjected to the most harmful conditions possible under operating conditions, which can subject it to premature wear. Insufficient lubrication may be mentioned among the main causes of this wear, engines operating at high loads expose the surfaces of the piston rings to a harsh process of wear, by wear or scuffing, among many other factors.

With the aim of minimizing wear and prolonging the service life of the piston ring 1, a covering or coating comprising a harder and wear-resistant material than that of the ring 1 is usually used on the outer working surface.

These coatings are usually deposited by ion coating processes. Among these processes, physical vapor deposition (PVD) is widely used.

The PVD process is atomic deposition in which the deposited material is vaporized from a solid source in atoms or molecules by a low-pressure gas (plasma) in the direction where the outside of the piston ring 1 contacts the substrate, condensing on the surface. The formation of a coating on a substrate depends on the vaporized material and the material of the substrate, the state of the substrate, the energy used (temperature and ion impact) and the atmosphere (chemical reaction, reactive deposition, etc.).

In this respect, the present invention discloses a piston ring 1 comprising a coating 4 having, as an essential feature, a multilayer construction, that is to say layers successively deposited to a certain thickness so as to provide excellent wear resistance. This coating 4 is preferably, but not necessarily, applied by a physical vapor deposition (PVD) process by the method of high-power pulsed magnetron sputtering (HiPIMS), and can also be applied by a cathodic arc deposition process.

The piston ring 1 of the invention allows a first preferred, but not mandatory, configuration in which the ring 1 is provided with a substantially annular base body 2 of iron alloy, on which base body 2 is coated with a coating 4 comprising a first The bonding layer 10 and at least the first outer layer 11 or the second outer layer 12 deposited on the first bonding layer 10, the thickness of the first outer layer 11 and the second outer layer 12 deposited subsequently can be up to 100 microns ( See Figures 1 and 2).

The first outer layer 11 consists of a doped nitride of a metallochemical element (x), the doped element being aluminum (Al), while the second outer layer 12 consists of a nitride of a metallochemical element (x).

The metal chemical element (x) is selected from chromium (Cr), titanium (Ti) or niobium (Nb). Thus, the first outer layer 11 consists of doped chromium nitride (CrAlN), while the second outer layer 12 consists of chromium nitride (CrN). In the same way, if titanium is used, the first outer layer 11 consists of doped titanium nitride (TiAlN), while the second outer layer 12 consists of titanium nitride (TiN). With niobium, the first outer layer 11 consists of doped niobium nitride (NbAlN) and the second outer layer 12 consists of niobium nitride (NbN).

The coating 4 of the piston ring 1 of the invention also includes the deposition of a second bonding layer 20 deposited on the first bonding layer 10 . The first bonding layer 10 consists of chromium (Cr) or chromium/aluminum (CrAl), while the second bonding layer 20 consists of doped chromium nitride, the doping element is aluminum (CrAlN) or chromium nitride (CrN) .

The first bonding layer 10 and the second bonding layer 20, as their names indicate, provide a bond between the base 2 composed of a soft iron material and the coating 4 composed of a hard material, from the soft material to the hard iron. The transition of the material ensures the adhesion of the coating 4 to the substrate 2. It should be noted that the deposition of the second bonding layer 20 is optional. In this case, the coating 4 comprises only the first bonding layer 10 .

The coating 4 comprises a thickness between 10 micrometers and 100 micrometers, so that the first outer layer 11 and the second outer layer 12 are provided with a thickness in the range of nanometers, a thickness of 1 nanometer, optionally 2 nanometers, which can be Selected as 3 nm, optionally 10 nm, optionally any size variation up to 200 nm.

The first outer layer 11 is provided with a thickness greater than at least one time, up to a maximum of ten times, the thickness of the second outer layer 12, resulting in the following thickness expression: 1<XAlN/XN<10, that is to say the first outer layer The ratio between the thickness of 11 (XAlN) and the second outer side 12 (XN) should be greater than 1 and less than 10.

From the expressions described, it is understood that the first outer layer 11 should have a thickness exceeding the thickness of the second outer layer 12 . This fact occurs due to the fact that the first outer layer 11 comprises the element aluminum (Al) doped providing low or no oxidation and high ductility. Such properties provide greater elastic deformation capacity on aluminum (Al), in this way able to absorb stress and increase wear resistance. In this way, the coating 4 in the form of outer coatings 11 , 12 provides high wear resistance and low internal stress due to the fact that the first outer layer 11 of the thicker coating 14 consists of aluminum (Al).

Furthermore, the coating 4 comprises a first outer layer 11 and a second outer layer 12 with periodic successive depositions, which can be extended to thousands of layers, including two deposits from the first outer layer 11 and the second outer layer 12 layers, three layers, four layers, five layers, six layers, 100 layers, 500 layers, 1000 layers, etc. The final deposited layer of the coating 4 will be the first outer layer 11 or the second outer layer 12 .

The main technical effect achieved by the invention is based on the fact that these layers act as interfaces or barriers that eliminate the propagation of cracks in the coating 4 , increasing in this way the resistance of the coating 4 from detachment from the substrate 2 .

In a preferred configuration, the PVD coating process of the present invention is carried out in a vacuum reactor comprising a cathode or material source for unbalanced magnetron sputtering (UMB) and high power pulsed magnetron sputtering (HiPIMS ), UMB and HiPIMS cathode act on the supply of coating material simultaneously.

The HiPIMS deposition process takes advantage of the phenomenon that exists to substantially increase the energy (greater velocity) that allows the ions to reach the metal substrate 2 where the growth of the coating 4 occurs, a considerable modification in the structure and organization of the coating 4 is observed.

The HiPIMS deposition process also allows ionization of the material, ie the usual metals (Cr, Ti, Mo, Nb, Al, etc.), before conversion to nitride. For its part, the high-energy acceleration of the metal ions striking the surface of the coating 4 allows a relaxation of the coating 4 to be obtained during the growth of the coating 4 without losing its hardness.

As a natural consequence of the high energy of the ions forming the coating 4 , especially the HiPIMS process, a significant densification of the coating 4 occurs, leading to a reduction in porosity and excellent adhesion of the ions on the substrate 2 .

Moreover, this procedure allows another benefit, offering the possibility to grow the coating 4 free from droplets (small particles). Thus, the HiPIMS procedure for the deposition of coating 4 allows to achieve excellent tribological properties such as wear resistance and detachment resistance.

It can be seen from Fig. 3 that the PVD coating process of the present invention includes at least two cathodes, i.e., the UMB cathode for depositing chromium aluminide (CrAl), and the deposition of chromium metal (Cr), constructed in the outer layer of coating 4 Alternating HiPIMS cathodes required in the deposition of 11, 12.

In another possible configuration, the PVD process of the invention comprises three cathodes, namely two UMB cathodes depositing chromium aluminide (CrAl), and a HiPIMS cathode performing the deposition of chromium metal (Cr).

The PVD process also allows a third possible configuration comprising four cathodes, namely, two UMB cathodes, a HiPIMS cathode depositing chromium aluminide (CrAl), and a second HiPIMS cathode performing the deposition of chromium metal (Cr).

It should be noted that the vacuum reactor contains an even or odd number of cathodes, choosing between one, two, three, four, five, six, etc., depending on each project and need.

In this way, the coating process of the invention allows the deposition of the outer layers 11, 12 at a nanoscale ratio of the replacement material, thereby improving the oxidation resistance properties, leading to low internal stresses while adjusting the process parameters, improving the resistance of fragments and Detachment of the coating.

Preferably, the PVD process of the present invention comprises a vacuum reactor provided with four cathodes, at least one HiPIMS cathode, and five stages of application of the coating 4 (see FIG. 4 ). They are:

Phase 1. Piston ring 1 is chemically cleaned and installed in a vacuum reactor. Before the piston ring 1 is installed in the reactor, the surface of the base body 2 of the ring 1 is cleaned with a chemical solution to remove all oil on the surface.

Phase 2. Reactor impingement and heating. To prevent any contamination, the piston ring 1 must be degassed. Phase 2 includes a temperature of up to 400 degrees Celsius at less than 0.00007 mbar (mbar) for 90 minutes.

Phase 3. Ionic pickling of the piston ring 1 provided by the HiPIMS cathode to clean the surface of the substrate 2. The bias voltage between the coating plasma and the surface of the substrate 2 provides an impact of chromium (Cr ⁺ ) on the surface to be coated, such a process being provided by sputtering of the surface. Phase 3 takes place in pure argon at a constant speed of 5 rpm (revolutions per minute), reaching a temperature of 400 degrees Celsius, a pressure of 0.001 mbar (mbar), a pulse frequency of 5.5 kW (kilowatts) and 100 Hz (hertz) of chromium, - Under a bias voltage of 0.1V (volts) and a duration of 30 minutes.

stage 4. Application of the multilayer coating 4 arranged on the base body 2 of the piston ring 1 . Chromium aluminide (CrAl) and chromium (Cr) cathodes are positioned alternately, on the outer surface of the base 2 of the ring 1 is deposited a triple material (CrAlN), a first outer layer 11, and a binary material (CrN), a second outer layer 12. It should be noted that chromium (Cr ⁺ ) is responsible for the ion impact of the coating 4 deposited on the surface, relieving the stress of the coating 4 .

Alternatively, stage 4 can be performed comprising only a second bonding layer 20 (CrAlN) deposited on a first bonding layer 10 (Cr), the second bonding layer 20 serving as a support layer for the coating of the outer layers 11, 12 . In this configuration, the second bonding layer 20 is sputtered by chromium nitride (CrN).

Stage 4 takes place in an atmosphere comprising a 50% mixture of argon and nitrogen at a temperature between 400 and 420 degrees Celsius and a pressure of 0.0022 mbar (mbar). The UBM cathode uses 8.0kW (kilowatt) and 23.0Hz (Hz) pulse frequency to deposit chromium aluminide (CrAl), the first HiPIMS cathode uses 8.0kW (kilowatt) and 400Hz (hertz) to deposit chromium (Cr), and the second Two HiPIMS cathodes deposit chromium aluminide (CrAl) using 8.0 kW (kilowatts) and 400 Hz (hertz). Phase 4 also takes place with a bias voltage of -65V (volts) and has an average duration of 600 minutes, varying according to the final thickness of the deposited coating 4 .

stage 5. Cool and unload piston ring 1. After finishing the application of the coating 4, the piston rings 1 were kept in the vacuum reactor so that the system cooled down to below 100 degrees Celsius, and then the rings 1 were removed and the coating process was restarted with new rings 1 to be coated. Stage 5 was initially at a temperature of 420 degrees Celsius until ambient temperature was reached, at a pressure of 0.0022 mbar (mbar) to atmospheric pressure, for 90 minutes.

Tests have been carried out on an engine to evaluate the wear resistance of the piston ring 1 of the invention and the adhesion of the coating 4 to the base body 2 of the piston ring 1 . The tests were carried out on three piston rings 1 of the invention installed in a high-load diesel engine and on two piston rings 1 of the invention installed in a high-speed diesel engine.

The first wear evaluation test was performed in a high-load diesel engine, and the ring 1 was delivered to an accelerated thermal shock test in a dynamometer for more than 250 hours, in which the state of thermal deformation of the engine block and cylinder liners, except for the oil film A bad state of cracking, especially observed on the working surface of the ring 1 . It should be further noted that, in order to minimize the variations involved as much as possible, the cylinder liner is obtained from the same production batch as the piston ring 1 .

Figure 5 presents the graphical results of the comparative wear evaluation tests described above, prior art I provided with a single layer coating 4 comprising chromium nitride (CrN) deposited by cathodic arc, while prior art II comprising The coating is similar to coating 4, but deposited by high power pulsed magnetron sputtering (HiPIMS).

The diagram of FIG. 5 additionally represents a piston ring 1 according to the invention in configuration I provided with a multilayer coating 4 comprising aluminum-doped chromium (CrAlN) deposited by cathodic arc deposition and successively deposited outer layers 11, 12 of chromium nitride (CrN); and configuration II comprising a coating 4 similar to that of configuration I, however deposited by high power pulsed magnetron sputtering (HiPIMS).

On the basis that the piston rings 1 of the prior art I and II exhibit a wear of about 4.0 microns, it can be clearly seen from FIG. The configurations I and II exhibited wear of 3.5 microns and 2.3 microns, respectively. In this way, configuration II of the piston ring 1 of the invention exhibits less than approximately 50% wear relative to prior art I and II. For its part, configuration I according to the invention does not clearly produce as good a result as configuration II according to the invention, but whatever produces a satisfactory structure, for use in internal combustion engines, proves, relative to the prior art Great benefit.

The second test was carried out in a high-speed diesel engine for more than 500 hours, using a piston ring 1 provided with a multilayer coating 4 comprising titanium-doped titanium nitride (TiAlN) as prior art II and in configuration II Piston ring 1 of the present invention. Again, the inventive piston ring 1 produced excellent results, revealing a wear of 2.3 microns, while the prior art III ring 1 exhibited a wear of 20.1 microns. In this way, the ring 1 of the invention exhibits less than approximately 80% wear compared to the ring 1 of prior art III (see FIG. 6 ).

Furthermore, the piston rings of prior art I, II and III exhibit detachment of the coating 4 from the matrix 2 , while the piston ring 1 of the invention ensures adhesion of the coating 4 to the matrix 2 .

It should also be noted that, through the hardness between 1800 and 2500HV (Vickers hardness) and the internal stress between 200 and 700MPa (megapascal), preferably between 300 and 600Mpa (megapascal), the present invention The coating 4 of the piston ring 1 exhibits a porosity of less than 6%, preferably a porosity of 3%.

The specific arrangement of the PVD process of the invention, together with the parameters of the process and the choice of materials, allows to obtain coatings with thicknesses up to 60 microns, without compromising the structure and mechanical strength of the coating.

The piston ring 1 of the invention is provided with a coating 4 with high wear resistance and low stress, in this way prevents the formation of large particles or discontinuities of structures leading to a high resistance to debris and prevents the coating 4 from dislodging from the piston The matrix of ring 1 is detached.

Having described an example of a preferred embodiment, it should be understood that the scope of the invention covers other possible modifications, being limited only by the content of the appended claims, including possible equivalents.

Claims (10)

1. the piston ring (1) for internal combustion engine, it is provided with substantially annular, the base of ferroalloy Body (2), is coated with the coating (4) including the first binder course (10), described ring (1) on the matrix It is characterized in that described coating (4) additionally includes:

At least one first outer layer (11) or one second outer layer (12), described first outer layer (11) and described Second outer layer (12) is deposited on described first binder course (10), described the first of multiple sequential deposition With the thickness that the second outer layer (11,12) reaches maximum 100 microns,

Described first outer layer (11) is made up of the nitride of the metallic chemical element (x) adulterated, described in mix Miscellaneous element is aluminum (Al),

Described second outer layer (12) is made up of the nitride of metallic chemical element (x),

Described first outer layer (11) is provided with a times of the thickness at least above described second outer layer (12) And the thickness of ten times of thickness less than described second outer layer (12).

2. piston ring (1) as claimed in claim 1, it is characterised in that described metallic chemical element (x) Select from chromium (Cr) or titanium (Ti) or niobium (Nb).

3. piston ring (1) as claimed in claim 1, it is characterised in that described first and second outer layers (11, 12) thickness between 1 to 200 nanometers it is provided with.

4. piston ring (1) as claimed in claim 1, it is characterised in that described coating (4) includes sinking Amass the second binder course (20) on described first binder course (10).

5. piston ring (1) as claimed in claim 4, it is characterised in that described first binder course (10) It is made up of chromium (Cr) or chromium/aluminum (CrAl), and described second binder course (20) is by the nitridation adulterated Chromium forms, and the element of described doping is aluminum (CrAlN) or chromium nitride (CrN).

6. piston ring (1) as claimed in claim 4, it is characterised in that described coating (4) is by described First and second binder courses (10,20) and described first and second outer layers (11,12) composition, in Reveal the hardness between 1800 and 2500HV (Vickers hardnesses).

7. piston ring (1) as claimed in claim 4, it is characterised in that described coating (4) is by described First and second binder courses (10,20) and described first and second outer layers (11,12) composition, in Reveal the porosity of 3% to 6%.

8. piston ring (1) as claimed in claim 4, it is characterised in that described coating (4) is by described First and second binder courses (10,20) and described first and second outer layers (11,12) composition, in Reveal the internal stress between 200 and 700MPa (MPa).

9. for obtaining an operation for the piston ring (1) for internal combustion engine as claimed in claim 1, It is characterized in that coating (4) includes the first binder course (10), the second binder course (20), the first outer layer (11) And second outer layer (12), deposited by cathodic arc deposition operation, or by physical vapour deposition (PVD) (PVD) Operation deposits, by the method for high power pulse magnetic control sputtering plating (HiPIMS).

10. an internal combustion engine, it is characterised in that it includes that at least one is lived as defined in claim 1 Plug ring (1).